Pneumatic-tube apparatus



1 ,624,078 Apnl 12 9 J. J. STOETZEL PNEUMATIC TUBE APPARATUS Filed April 17' 1926 ATTORNE Patented Apr. 12, 1927. I

UNITED. STATES PATENT OFFICE. v

. A JOSEPH JOHN STOETZEL, OF QUEENS VILLAGE, NEW YORK, ASSIGNOB TO G. 86 G.

ATLAS SYSTEMS, INC., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

rnnum'ric-runn arrnm'ros.

Application filed April 17, 1926. Serial No. 102,675.

This invention relates to improvements in pneumatic tube apparatus, and particu larly to the controlling devices for controlling the flow of air through the system.

The object of my invention is to provide such a controlling device which is sensitive to the pressure conditions within the system and which, as a result, will automatically regulate the amount of air flow in accordance with the load imposed upon the-system at all times. I In my copending application, Serial No. 62,965, tiled Oct 17, 1925, I have disclosed a controlling device which in many Ways resembles the controlling device of my present invention. The valve of said copending application is, however, so constructed that it is always in one of two positions. That is, it is either in its closedposition or in .its fully open position. According to my present invention the valve is closed when no carrier is being transmitted, and

when one or more carriers are being trans mitted it is opennot fully open alwaysbut at all times open just enough to establish the amount of air flow that the load requires.

The principal structural difierence between these two devices is that in the device of my copending application the valve opens in a. direction against the current of air flow, Whereas in the device of my present application the valve opens in the direction of the air current. As a result of this arrangement my improved device operates not only to govern the amount of flow while carriers are bein transmitted, but serves also as a relief va ve for cooperation with a constant speed suction producin device to relieve excessive loads thereon w en no carrier is in transit.

in the accompanying drawing, Fig. 1 illustrates a conventional pneumatic tube system to which my present invention is applicable; Fig. 2 is a longitudinal sectional View of the controlling device of my invention; and Fig. 3 is a detail view taken on the sectional line 3-3 of Fig. 2.

The pneumatic tube system shown'in Fig.

1 embodies the vacuum drum 10, the suction tube 11 and the transmitting tubes 12, 13 which are connected by the intermediate terminal 14 in the manner well understood in the art. At the intermediate terminal there is the carrier exit 15 controlled by the nected the flexible diaphragm or other pneumatic device 22 for opening the valve, as will be describedlater. This diaphragm 22 divides the casin 23 into two chambers, namely, the cham er 2 1 to the left of the diaphragm, which is open to the atmosphere through t'heoritice 25, 'and the chamber 26 at the right of the diaphragm, which is in communication with the transit tube 11 through the passage 27. By reason of this communication the chamber 26 is normally maintained at the pressure existing within the transit tube 11 above the controlling device.

The valve 20 is normally held in the closed position shown in Fig.2 by the relatively strong spring 29 which surrounds the right hand end of the valve stem 21 and the .tension of which may be adjusted by .means of the adjusting sleeve 30 which may be held in adjusted position by the lock nut 31. In referring to the closed position of the valve 20 I mean the position such as shown in Fig. 2, in which the valve is held slightly ofi lts seat to permit of a slight flow of air through the orifice 19. The amount of this opening, and therefore the amount of minimurii' flow, is determined by the position of the adjusting screw 32 which contacts with the left hand end of the valve stem 21. I

The passage 27 between the diaphragm chamber 26 and the transit tube 11 is preferably provided with an opening 33 to the atmosphere, which is controlled by the poppet valve 34:" normally held closed by gravity. This poppet valve is mounted on one endofa pivoted lever 35, the other end of which extends within the transit tube and is provided with a vane 36.

The particular point of interest in the controlling device I have just described is the fact that the valve 20 opens with the currentof air flow instead of against it, as in the case of my copending application.

the tube the minimum flow is maintained as above described. If, however, the minimum iiow provided by the adjustment of the jscrew 32 should prove insufficient to prevent the suction producing device from building I up an excessive vacuum in the suction drum,

then that vacuum will operate upon the valve and open it slightly so as to permit a larger minimum flow and thus reduce the vacuum in the suction drum to the desired amount. Of course, if there are a number of lines connected to a single suction drum,

, as is usually the case, the operation of a single one of the controlling devices as a relief valve would usually take care of any excess of vacuum formed in the drum.

Turning now to the operation of the valve upon the insertion of a-carrier and during its transmission, when the carrier is inserted in the bell-mouth 17 or the intermediate en'- trance 16, it acts as a plug, stopping the communication between the controlling devices and the atmosphere through the bellmouth. As a result, the minimum flow through the orifice 19 rarefies the air in the diaphragm chamber 26 so that the atmospherie pressure within the diaphragm chamber 24 exerts a pressure on the diaphragm tendin to push it toward the right to open the va v'e. This unbalanced pressure and. tendency to ogen the valve is augmented by the unbalance pressure on the valve 20 and the kinetic energy of the flow of air-through the orifice 19. These combined'ifactors result in opening the valve against the pressure of the spring 29. This spring, however, as above described, is relativelystrong compared, for example, to the corresponding spring in m copending application, and as t e result, i the loadin the line is reduced, as for example b the carrier passing through a vertical op in the line, the decrease in the vacuum within the diaphragm chamber 26 permits this spring to partially or wholly close the valve 20. When the carrier again imposes a greater load upon the line the valve will ,be again'opened as above described.

When the carrier leaves the line there is an immediate rush. of air through the line, and this rush of air may be. utilized through vthe vane 36 to ppen the poppet valve 34'and thus admit atmospheric pressure to the diaphragm chamber 26 to assist in closing the valve'20; Because of the strong spring 29,

which my present arrangement makes pos-.

sible, ll find it unnecessary to employ any vane 36 and its cooperating parts for closing the valve 20 except in excessively long lines, and even in such lines I find it can be dispensed with Without serious inconven-. ience or loss of eficiency.

I have referred above to the fact that my present structure permits me to use a relatively strong spring '29. The reason this is permitted is because the valve 20 opens as a relief valve in the direction of flow of the air current and therefore, as above devices of similar construction. the valve opens in the direction against the air current. As the result, the spring which normally tends to hold the valve closed has to be relatively light or otherwise the unbalanced pressure on the diaphragm resulting from the insertion of a carrier would be insuficient to open the valve against the direction of current flow. Accordingly, the valve of my copending application operates; as a snap valve, snapping open upon the insertion-oi a carrier and then snapping closed again upon the exit of the carrier. It has no intermediate position. The distinction between such operation and the operation of the device described herein is believed obvious.

- I may apply my present invention to controlling devices of various forms, the particular form shown in the drawing being merely one illustration of the application of this invention,

' The terms and expressions-which have employed are used as terms of descr ption and -not of limitation, and l have no intensions; of excluding any equivalent of features shown and described, or portions there- 7 of, but recognize that various modifications are possible within the scope of the invention claimed. 7

I claim: 1

" '1. In a pneumatic tube system, a transmitting tube, a casing communicating Wltll' said transmitting tube and provided with an orifice, means for producing a flow of a1r through said orifice, a valve for sa1 d orifice adapted to control the flow of air theresaid valve bein adapted to open 111 throrzfilh, the ection of said ow, sprmg means tending 'to close said valve, and means re- -tion, in the use of such terms and expressponsive to the pressure conditions in the,

transit tube for opening said valve.

2. In a pneumatic tube sys em, a transmitting tube, a casing communicatin with said transmitting tube and provide with an orifice, vacuum producing means beyond said casing adapted to produce a flowof air through said orifice, a valve for said orifice adapted to control the flow of air therethrough, said'valve being adapted to open in the direction of said flow, spring means tending'to close said Valve, and means responsive .to the pressure conditions in the transit tube for opening said valve:

3. In a pneumatic tube system, a transmitting tube, a casing communicating with said transmitting tube and provided with an orifice, means for producing a flow ofair through said orifice, a valve for said orifice adapted to .control the flow of air therethrough, spring means tending to close said -Ive, means normally holding said valve slightly open to permit a slight flow through 'Whereby said valve automatically said orifice, the means for producing the flow of air through said orifice being adapted to exert pneumatic force on said 'valve in the direction of its opening, whereby said valve responds to an excess of such force by opening andv thus relieves such excess.

In" a pneumatic tube system, a transmitting tube, a casing communicating with said transmitting tube and provided with an orifice, vacuum producing means beyond said casing adapted to' produce a flow of air through said orifice, a valve for said orifice adapted to control the flow ofair therethrough, spring means tending to close said valve, means normally holding said valve slightly open to permit a slight flow through said orifice, said vacuum producing means being adapted-to exert pneumatic force, on said valve in the direction of its opens to relieve any excess of vacuum which may be produced by said vacuumproducing means.

JOSEPH JOHN STOETZEL.

opening, 

